Severe WX Questions...More Advanced...

[btritch]

I have a couple of questions that maybe someone more advanced than me can answer for me, I'm pretty sure I know the answer to the question but I want to make sure that I am on the right track here with this, I have found a little bit of information online but not enough to really understand and prove my theory but can anyone on here that's more advanced in weather and technology than me tell me the following two things...

1) What exactly is A hook echo?
and also this one:
2) What is The Downburst of the storm?

Any help will be appreciated.. Thanks..

Brian Tritch
N.E.A. Local Weather Watcher/Spotter
KAIT 8 TV Jonesboro Arkansas
http://www.kait8.com/Global/category.asp?C=98226

Thanks Again!

 

[Jimmy252]

Downburst:

A downburst is a localized area of damaging winds caused by air flowing down and out of a thunderstorm. To create a downburst at the ground, the downdraft speeds in the thunderstorm must be unusually high, and this downward flowing air must penetrate close to the ground. These conditions can be met when the boundary layer air is relatively dry, and when there is plenty of falling precipitation. It is not necessary for the thunderstorm to produce hail or tornadoes to produce a downburst. Damage from downbursts can be so severe that it is mistaken for tornado damage. When examined, however, the damage pattern from a downburst will be divergent, indicating the winds were flowing outward, rather than in a circular pattern as in the case of a tornado. Downburst damage can cover hundreds of square miles, or be limited to a single field (the smallest ones are called "microbursts").

 

[btritch]

I must've had a microburst then, It's just my area and one area around the corner and one more area across town that had what looks like tornado damage, there were no confirmed funnels but there were confirmed wall clouds..It was classified as a downburst on the end of a hook echo. That's why I asked about both. I thought that's what a downburst was, I was pretty sure on that, it's the hook echo that got me.. I was thinking a hook echo was a rotating cloud that actually had rotation such as a funnel in it but wasn't vertually on the ground. An in the air funnel but I'm not sure I'm right on that.. I hit the Micro/Downbust right on the head though.. Roofs ripped off and trees shredded and broken off.. Chicken coops tossed! I'm still unsure on the hook echo though.. Anyone sure?
Note: Out of all these places, I GOT THE WORST damage.. Therefore Hence the term Microburst.. LOL

 

[Jimmy252]

A hook echo is a "break off" of a storm, much like a peninsula on land, which can rotate rapidly. Here is a diagram....

 

[Jimmy252]

This hook ismore defined. As you can see, on the lower left side of the storm, the rotating column breaks off from the main cell.

 

[btritch]

got it thanx

 

[KB3KBR]

normally most hooks are associated with a tornado or funnel cloud. Hook (or Hook Echo) - A radar reflectivity pattern characterized by a hook-shaped extension of a thunderstorm echo, usually in the right-rear part of the storm (relative to its direction of motion). A hook often is associated with a mesocyclone, and indicates favorable conditions for tornado development. http://www.srh.noaa.gov/oun/severewx/glossary2.php#Hook

 

[btritch]

Ok, The reason I was wondering is cause I have some damage around here, Roof Blown off a building, Chicken coop and dog pen tossed like candy, Fence thrown through plate glass windows, House roof's damaged, Antenna's damaged, Siding damaged, Trees Broken off and snapped like twigs at the ground. My local news media and NOAA and also the NWS are saying it was a Downburst or a microburst embedded into a hook echo but the last time I checked, Hook Echo's and Downbusrsts Do not cut paths through the water like a boat...This did..

 

[Jimmy252]

im thinking u had some sort of vortex on the ground. Dustnado or gustnado, not classified as a tornado but is a ground vortex that can cause damage. They are usually associated with gust fronts on severe storms...

 

[btritch]

I bet that was it then.. All I know is I thought the ROOF was coming off. I'm usually in them watching them for the TV Station that's tracking them but I didn't have a chance this time. It was BOOM and it was upon me! LOL

 

[rdale]

normally most hooks are associated with a tornado or funnel cloud.

No. Hooks CAN have a tornado or funnel, but certainly not MOST.

 

[ka5lqj]

Grateful.....

Well,

All I can say is that I'm grateful no one was injured or killed. Down here in the Ark-La-Tex, we certainly have our fair-share of bad wx. I've been active in Skywarn here for over 25 years as a "spotter", "chaser", and now, just a "helper" trying to hear the distant, oulying, stations that quite can't seem to make the 146.67 wide-area repeater.

Hearing of a severe wx event is never pleasant, whither local or not. I always pray for those in the path of those events for their, their family and friends safety and minimal damage.

Respectfully submitted,
73,

Don/KA5-LQJ

 

[LukeB]

I believe a determining factor for a tornado vs downdraft is that a tornado will have twisted debris due to the motion of the storm.

 

[rdale]

No. All debris can be twisted (imagine a straight wind blowing a piece of siding towards a pole -- it'd wrap around.)

One of the ways we can tell is by looking at the pattern of the wind damage. If it spreads out from a single track, it's likely downburst. If it's wrapped in towards a track, with debris on all sides of a house, it's likely tornado. We also use radar data to help.

 

[HogDriver]

No. Hooks CAN have a tornado or funnel, but certainly not MOST.

I would say that, at least here in Oklahoma, about 80% of the storms have hook echoes that do NOT end up dropping a tornado. Hook echoes are an indicator of rotating winds inside the lower levels of the storm but unless you have a strong enough downdraft to pull it down, amongs other "perfect" conditions, you won't have a tornado.

Wunderground has a feature on their NEXRAD radar page that allows you to view the winds in a storm. It works quite well showing this rotation.

Lastly, the damage must be examined if a sighting by a trained, reliable spotter was not made to determine if in fact it was a tornado, or just straight-line winds from a downburst or such. Straight-line winds can most often be found at the leading edge of a gust front. This is indicated on the radar by a bow-shaped area forming as the particular storm is collapsing and is found under the shelf cloud as the gust front.

 

[rdale]

I would say that, at least here in Oklahoma, about 80% of the storms have hook echoes that do NOT end up dropping a tornado. Hook echoes are an indicator of rotating winds inside the lower levels of the storm but unless you have a strong enough downdraft to pull it down, amongs other "perfect" conditions, you won't have a tornado.

80% is probably right... A MASSIVE hook from a storm along the OK/TX border on Monday night had many "radar watchers" thinking monster tornado for a long track - and just a minor spinup touched down for 30 seconds.

 

[UPMan]

Here are some additional great resources for storm (and storm spotting) info:

http://www.nws.noaa.gov/om/brochures/basicspot.pdf

http://www.nws.noaa.gov/om/brochures/adv_spotters.pdf